1. Field of the Invention
The invention relates to a method for the data exchange of peripheral data between a main module and a submodule, where a peripheral unit is connected to the submodule and data are read in or output using the peripheral unit.
The method comprises defining a peripheral transfer data record having a first address range of a peripheral unit and a second address range of a main module, and mapping the peripheral data prevailing in the first address range into the second address range and/or mapping the peripheral data prevailing in the second address range into the first data range.
The invention also relates to a submodule for exchanging peripheral data with a main module, comprising an operating system, an application program for implementing control tasks, and an interface, which is configured to read in data from a peripheral unit and/or output data to the peripheral unit.
2. Description of the Related Art
In the area of field buses, such as the Profibus Decentralized Peripherals (DP), methods and control systems are known in which a superordinate controller is connected to a field bus and the field bus is in turn connected to automation units, which represent a decentralized peripheral system. In general, the automation units are designed as input/output assemblies and can be directly connected to sensors and actuators in an automation installation on site at the machines. The decentralized input/output assemblies can be connected to a main module directly or to the main module by a submodule. In the latter configuration, a commissioner in the case of an automation installation of this type is faced with the problem of correspondingly mapping the input/output addresses of the decentralized peripheral system to address ranges in the main module. For this purpose, in accordance with conventional practices, in an application program of the submodule, for example, where the application program is designed as a cyclically executed programmable logic controller (PLC) program, the assignment is performed using a copy mechanism.
In addition, functional components, such as DB-send and DB-receive are available in the application program. The peripheral data of the input/output units are read in from the submodule and stored in a data component, where an assignment to an address range in the main module occurs and the address ranges thus assigned or the data contents thereof are transmitted to the main module under a transmission command. The application program copies the input/output data of the decentralized peripheral system and makes them available over a data interface to the superordinate main module. As a result, the superordinate main module is additionally burdened with computational complexity. This additional burden is associated with an execution time of the application program in the processing cycle of a programmable logic controller.
The run time of this application cycle has the critical responsibility of ensuring that the input/output data is up-to-date. For an installation operator with an industrial automation installation equipped with automation devices that forward decentralized peripheral data to a superordinate main module, it is important on account of an optimized control process to obtain the peripheral data at the “correct” point in time. Moreover, for the installation operator it is desirable for the application program not to be concerned with unnecessary copy tasks.